Microencapsulation of chemical additives

Abstract

The present disclosure relates to new and optimized processes for the preparation of micro- and nano-scale capsules containing lubricant chemical additives. The present disclosure also relates to micro- and nano-scale capsules prepared by such processes, which are useful in a variety of applications, including automotive lubricants, diesel lubricants, industrial lubricants, metal-working lubricants, coolants, and process fluids. Micro-and nano-scale capsules prepared as described herein have the required properties that such capsules need to exhibit in order to function effectively and meet the requirements imposed by engine lubrication conditions. The microcapsules may be dispersed in a lubricating oil such that the lubricant exhibits improved stability and anti-wear performance, thereby improving engine fuel efficiency and performance.

Description

[0001]This application is a national stage of International Patent Application No. PCT / US2015 / 031090, filed May 15, 2015, which claims the benefit of U.S. Provisional Application Nos. 61 / 993,805, filed May 15, 2014, and 62 / 056,968, filed Sep. 29, 2014, the entire contents of each of which is hereby incorporated by reference.FIELD OF THE INVENTION[0002]The present invention relates to new and optimized processes for the preparation of micro- and nano-scale capsules containing lubricant chemical additives. The present invention also relates to micro- and nano-scale capsules prepared by such processes, which are useful in a variety of applications, including automotive lubricants, diesel lubricants, industrial lubricants, metal-working lubricants, coolants, and process fluids. Micro- and nano-scale capsules prepared as described herein have the required properties that such capsules need to exhibit in order to function effectively and meet the requirements imposed by engine lubrication...

AI Technical Summary

Benefits of technology

[0011]Additionally, microcapsules prepared by the processes described herein retain their original functionality so as to function in high hostility environments, such as the high temperature (>150° C.), high shear stress (GPa levels) and contact pressure (up to ˜800 MPa) mechanical environments found in, e.g., operating engines (such as in cars and trucks) containing sliding interfaces, with high mechanical loading and high temperatures (e.g., piston ring-cylinder liner interfaces), transmission gears, wind turbine gears and highly stressed shearing interfaces of steel parts, making them ideal as lubricant components in such environments.

[0107]In another embodiment of any of the processes described herein, a single capsule (“a mother capsule”) having a size of between, for example, about 5 to about 100 microns or about 2 and about 40 microns (such as about between about 5 and about 28 microns) may contain one or more smaller capsules having a size less than, for example, about 2 microns (such as less than about 1 micron, or in the nanometer range). When the mother capsule releases its contents (i.e., when the mother capsule is triggered), the one or more smaller capsules may, for example, enter the sliding bearing interfaces of an engine and provide antiwear action, thereby reducing the attrition of the one or more smaller capsules being entangled by viscosity modifiers, dispersants, and other chemical and mechanical interferences.

Problems solved by technology

Therefore, the kind of chemical agents that may be encapsulated are limited to relatively pure compounds and mixture of simple chemicals.

When using polymeric capsules, the mechanical strength and associated properties usually cannot withstand constant shearing, high contact pressures, or combination of high temperatures and pressures such as those encountered in engine lubricant applications.

Complex additive compounds (such as a complex mixtures of molecular weights, functional groups, and / or compounds with nanoparticles embedded into the molecular structures) including dispersants, detergents, overbased materials, and antiwear agents have not been successfully encapsulated due to their complexity and charge driven aggregation tendencies.

The combination of a hostile chemical environment and a highly stressed mechanical environment typically renders conventional microencapsulation technology ineffective.

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